In the medical field, catheters and other medical devices are commonly packaged in molded plastic trays with various indentations and compartments for holding securely and neatly in place the various parts of the device, such as the coil of a catheter, the connector between the catheter and the extension tubes, and the extension tubes. The package is then heat-sealed with a thin flexible lid having adhesive backing, and sterilized with the device in the package.
The lid is generally made from a polymeric sheet material that provides a breathable, sterile barrier and then coated on one side with a heat sealable coating, usually a hot melt adhesive system. Raised surfaces or rims are formed around the periphery of the tray to provide a surface for heat sealing the lid onto the tray. Tabs are usually formed in the lid so that the lid can be easily grasped and peeled open when the medical device is needed.
There are times when it is desirable to peel or tear open only a portion of the lid to gain access to a portion of the medical device, usually the noninvasive portion, while retaining the sterility of the other portion of the device, usually the invasive portion, that is, the portion that enters the patient's body. Lids have been provided with two tabs, one for peeling open one portion of the lid to expose one compartment of the package and one for peeling open the other portion of the lid to expose the other compartment of the package. In practice, however, the portion of the lid the user intends to peel or tear open sometimes tears over to expose the other compartment, risking contamination of the invasive portion of the device. The shredding that results allows loose particulate matter to enter the compartment, increasing the likelihood of contamination.
Sealable and sterilizable packages with heat sealed, peelable lids have also been used in the food packaging industry. See, for example, U.S. Pat. No. 3,946,871, issued March 30, 1976, in the name of Sturm, for a Sealable and Sterilizable Package. There have been other prior art containers with membrane type closures that can be partially torn open along a defined tear line to form a dispensing opening. See, for example, U.S. Pat. No. 4,209,126, issued June 24, 1980, in the name of Elias, for a Patch Top Closure Member Including a Monoaxially Oriented Film Layer. In Elias, the defined tear line is achieved by providing a lid with at least one layer of mono-axially oriented plastic film having a grain pattern parallel to the desired tear line and providing a tear-initiating cut at the periphery of the lid adjacent the tear-initiating tab. In Elias, there is no attempt to control the direction of the tear line as in the present invention.
There is a need for a package having a peelable lid and means for controlling the direction of tearing open the lid, while providing a clean tear line and reducing the amount of particulate generated by the tear. This need is especially felt in the medical field where it is desirable to peel open only one portion of the lid at a time in order to perform preparatory tasks, such as calibrating the medical device.
It is therefore an object of the present invention to provide a package having a peelable lid and means for controlling the direction of tearing open the lid, while providing a clean tear line and reducing the amount of particulate generated by the tear.